Hi! New to Pinhole Photography and have an exposure question.

Hi out there. This looks like a fantastic site, and I intend to dig in more as time allows.

I have just constructed my first pinhole camera from an old kaput Ricolet 35mm camera. I used a clever little calculator from Mr.Pinhole.com, and all seemed just fine. I took it out today (slightly overcast evening w/snow), using the light meter in my Nikon N80 as my source before making the calculations per the Mr. Pinhole Light Exposure Guide. Well it would seem I was all set, but I forgot to set my N80 for ISO 100 (the film used in the Ricolet PH camera) and instead, the N80 defaulted to ISO 6!!!!! Details: focal length: 28mm, pinhole aprox .2mm so f124 or there about, ISO 100 Kodak Tmax film.

Sooooo, my gut feeling is that this roll is completely blown out as a result, but being new to pinhole photography and the little differences inherent to it, I thought I would ask before throwing the film out.

I hate to blow money on development if this roll is shot, but do you all think it's worth giving a whirl at my local pro photo developer?

I do not have a darkroom at this time, though I'm working toward it. I'm also not a professional photographer - mostly a painter/drawer and musician. But I LOVE photography too and want to explore this pinhole stuff fully.

Well, things will no doubt be a bit to the bullet-proof side, but knowing what film you used might help create a more precise guess. Negative films have pretty good tolerance for over exposure. But also, some films have considerable reciprocity loss at long exposures; that is, if the reading called for 5 seconds, you might actually need 8 or 10 anyway. If both situations apply to your case, you might get something usable. If it was slide film, things will probably be pretty washed out.

Thanks for the reply! I need to research the reciprocity factor a little more to better understand it. My biggest concern was that the discrepancy was too severe. I just took a reading on something that gave me a reading of 1 second at f.16 for ISO 6, which when converted to f.124, translates to just over 1 minute, where as, a reading taken for ISO 100 at f.16 gives me 1/10 translating to a 6 second reading at f.124 on the same subject (6 seconds v/s over 1 minute.) So I'm still a little worried given that this is a lot longer than a few seconds one way or the other, but it's good to know neg film is easy going about these things. In the end it's only about $7 to process plus a contact sheet, but if you think it's a totally lost cause at that discrepancy point, I can chuck it.

Ah, I see you are in SE PA too. Where at, if you don't mind my asking? I'm out in Western Chester Co.

Auto focus. The N80. I suppose you could go that way. That's the cool thing about pinhole photography, or photography as a whole for that matter. It can be as exact or as abstract as you like.

For myself, I usually throw down some pinhole when I'm burnt out a bit with my regular photography and just need to walk around with a camera that looks even more ridiculous to the unaware lookers-on. I've got some basics figured ahead of time and just point and uncover by a rough Sunny-16. I leave the meters at home. Of course, my pinhole is a couple of 35mm cannisters affixed to the sides of a matchbox so a meter would be overkill for me.

I've seen some things about those tiny pinhole cameras made with a matchboxes once before, might have to try one. I've been thinking of converting a couple of cigar boxes for 120 too, but wanted to test things out with a slightly modified "real" camera first for the sake of familiarity. Recently purchased a Holga too. Looking forward to what that puppy may yield. I love my N80, but it's so crisp that sometimes I long for mixing in a little grit and mystery.

In a bit more detail about reciprocity failure .... At long exposures, going from say, 1 minute to 2 minutes, does not double the effective exposure. You might have to go to 3 or 4 minutes, but it is very film dependent. ISO 6 vs 100 is about 4 stops: sqrt(100/6) over exposure. Depending on the specific film (you haven't told us what it was) an exposure metered in the 1 minute range could call for as much as five minutes or more of additional exposure to get over reciprocity failure. In other words, if you didn't already compensate for reciprocity failure, especially allowing two stops of exposure latitude, you might well be almost dead on! But some films are much less deviant in that matter, and also not everyone here agrees with the numbers. I tend to take my pinhole work as very loose and seat-of-the-pants and I would probably go ahead and get the film processed -- but I don't want to decide how you should spend your money!

I might look at how processing cost compares with the cost of another roll of film. And as I say, I think you might be close enough that it will provide some useful results, perhaps the high end data points for your next roll. Now if I was faced with paying $16 to get a $3 roll of slide film processed, I might toss it and try again.

I live in Montgomery County, sort of central. In my rambling PBase galleries, you may see stuff you recognize.

John, the best thing to do, which is easy with roll film, is to run a quick test to determine the best exposure. On a bright, sunny day, find a scene containing blacks, grays and whites. Make six or eight exposures of the same scene over a six or eight stop range. Try 1/4" 1/2" 1" 2" 4" 8" 16" 32". Somewhere in the set of exposures is the best one. More than likely you'll be able to tell by looking at the negative and finding the one with the most detail in shadow and highlight. That exposure will be your "magic number" or your "sunny 16" number. Adjust your exposure by the difference, in stops, between bright sun and ambient conditions. If you used your Nikon to make a meter reading when making the set of exposures, you can use it in the future to help you make the adjustments for ambient light.

Let's say the best exposure was 2" and the Nikon said 1/100" at f16 at ISO 100. If you make an exposure on a hazy day, and the Nikon says 1/50" at f16 at ISO 100, you'll need to make the pinhole exposure one stop longer (two times longer). So your pinhole exposure will be 4" If the day is overcast, and the Nikon says 1/25" at f16 at ISO 100, you'll need to make the pinhole exposure two stops longer (or four times longer), or an 8" exposure.

This is actually a simple system, if you understand the rudiments of photographic exposure. In practical use, you don't need to worry about reciprocity failure, since your initial test was done with such a long exposure.

This next comment is unecessary, but I'll make it anyway. I use an indicent light meter set to display Exposure Values, which makes the process of determining the difference between sunny 16 and ambient light even simpler (except for the learning about exposure values in the first place, which is why the comment is unecessary).